Moderators: Random Orbital Bob, nev, CHJ, Noel, Charley

By novocaine
I can see a mitre fence and maybe a little jig in your future. making cavity covers for guitar tonight. Will play with an offcut hopefully tomorrow on the band saw and the scroll saw.
By Chris152
Thanks novocaine - haven't used the mitre guide since I bought the saw, didn't even occur to me! This is done by eye and the mitre guide on 30 degrees without markings or stops but I can see that it could work fine - especially with a thinner blade with minimum set, producing a thinner gap between the teeth of the comb (these are about 5mm). It'll need either a lot of care or some kind of stop to ensure all the teeth are the same length (some of these wouldn't touch the surface).

Front and back will be sanded to bring the teeth closer to a point (about 3mm depth remaining at the tips).
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By novocaine
yep that works.

I think what I'd do is make a jig that rides on the mitre slot instead of using the fence.
A piece thats 18x400x60 fit a runner to the base of it so sits at the 30 degrees mark and extends a good 100mm past the blade. you can then do a small initial cut in the front of it to the depth you want the teeth to be (about 10mm so you get a bit of extra). from that mark out each cut across the jig, you can drill holes and put pins in if you want so you move the pins each cut and have something to register against.
this needs a drawing. just a mo.

comb sled.jpg

something like that. if you feel comfortable with registering against lines you don't need the registration holes. or you could incorporate the holes in to the design of you comb so you slot 2 pins in the comb, cut it out, flip it, do the same then claim the holes are for lanyards. :D
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By Chris152
That looks great - my feeling is I'll do better at first go with just accurate lines to work to, drilling one hole slightly in the wrong place would result in a dud tooth/ having to remake the jig. I'm off hunting for wood today so it'll have to wait, but meantime I'll put an order in for a new blade as above. I'm thinking to make them from oak, ash or beech (i have plenty of offcuts), cutting into end grain for strength of the teeth - sound ok?
Thanks for the drawing novocaine, really appreciate it.
By novocaine
dont use oak. sea water and oak aren't best of friends (someone will tell you about their oak boat and how it's never been an issue shortly).
white woods like ash and beach are a good choice IMHO, found the guy (who appears to to be 2 girls now) in cornwall on etsy (who knew)

drilling holes accurately, you make a jig for that. :) a block with four holes drilled perfectly (only need to get 4 right). a pin in 2 of the holes and the other 2 are the guide. drill the first 2 holes in your comb jib, insert the drilling jig and drill the next 2, then advance the drilling jig to those holes and repeat. :)
By Chris152
A jig to make a jig. :-) That sounds do-able, though.
I searched for those handmade ones, no joy but good to see them and they're selling. Once I've got the teeth sorted, it's all down to design I guess - i was thinking something more substantial - the truth is, even with cold water wax, come winter you need a fair bit of pressure on cold days and something that sits back into the palm more is good. And less teeth / bigger spaces is good too, to a degree - more teeth need more pressure. Well, that's my marketing line sorted. :wink:
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By ColeyS1
Myfordman wrote:Isn't Bamboo the ideal stuff to use for strength in small sections?
Not sure, but its bloody hard stuff. I made something from some left over flooring and it wrecked a champfer cutter.
Looks like you've got it sussed out Chris ;@)

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By Chris152
Myfordman wrote:Isn't Bamboo the ideal stuff to use for strength in small sections?

I guess it's good, tho most are made from plastic. But I'm trying to work with local woods more generally and it'd be a shame to change that - plus, local hardwoods, as well as being strong enough, look far better I think.
By Chris152
I made a jig as per, which seemed fine in itself but the slack of the mitre guide in the track was enough to allow some teeth to be different sizes (and hence lengths) to others. Sooo, I went back to plan b and marked up some ash 4mm spaces along one edge and a depth of 7mm, and cut by eye using the mitre guide at 12.5 degrees iirc (whose movement didn't matter as I was relying on seeing the wood was correctly aligned). It took 20 mins to make this from initial cut of a block through oiling, and I'm pretty pleased with it.
Teeth cut:

Teeth sanded back and finished:


You can see a couple of the teeth began to disintegrate as the tip was cut so next time I'll leave a tiny flat surface to the tips of each tooth, or sand them flat after [edit - looking at the first photo, they don't seem to have done it in the cutting so maybe it happened when sanding - I used a drum rather than a flat sander so that might sort it]. And I'll allow the teeth to follow the direction of the grain - this was just an off-cut to see if I cut cut the teeth accurately enough - and try to cut a more interesting overall shape. This test's definitely good enough to use, which we'll do tomorrow at the crack of dawn!
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